The disclosure relates generally to processes for sintering, such as sintering green tape including polycrystalline ceramic grains or other inorganic particles, bound in a binder, as well as continuous and discrete sintered articles, such as ceramic sheets, tapes or ceramic pieces made from such processes. The disclosure relates articles, such as thin sheets, tapes, ribbons or pieces of ceramic or other inorganic materials that have many potential uses, such as serving as waveguides, when the ceramic is transmissive to light, serving as substrates that may be coated or laminated, and integrated in batteries and other components, or used as or joined with a substrate such as to act as a dielectric in an electronics package (e.g., LED package), or other applications. Various material properties, particularly of ceramic materials, such as high resistivity, low reactivity, low coefficient of thermal expansion, etc. make such articles particularly useful in a wide variety of applications.